9SOK: Three-domain single chain TCR-581

Structure of three-domain single chain TCR-581 in complex with Peptide-HLA. Determined by X-ray diffraction at 2.5 Å resolution. Released 16 Sept 2026.

Method: X-ray diffraction
Resolution: 2.5 Å
Organism: Homo sapiens
Chains: 4
Atoms: 6,054
Mol. weight: 87.43 kDa
Released: 16 Sept 2026

Explore 9SOK in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9SOK contains 22 α-helices and 67 β-strands across 4 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 10 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-14	12	1
β-strand	18-28	11	1
β-strand	31-37	7	1
β-strand	46-47	2	1
α-helix	50-52	3
α-helix	57-84	28
β-strand	94-103	10	1
β-strand	109-118	10	1
β-strand	121-126	6	1
β-strand	133-135	3	1
α-helix	140-149	10
α-helix	152-158	7
α-helix	159-163	5
α-helix	164-174	11
α-helix	176-179	4
β-strand	183	1	2
α-helix	184-185	2
β-strand	186-193	8	3
β-strand	198-208	11	3
β-strand	209	1	2
β-strand	214-219	6	4
β-strand	222-223	2	4
β-strand	228-230	3	3
α-helix	231-233	3
β-strand	234-235	2	3
β-strand	241-250	10	3
α-helix	254-256	3
β-strand	257-262	6	4
β-strand	270-273	4	4

Chain B: 2 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	3	1	5
α-helix	4-5	2
β-strand	6-11	6	6
β-strand	21-30	10	6
β-strand	31	1	5
β-strand	36-41	6	7
β-strand	44-45	2	7
β-strand	50-51	2	6
α-helix	52-54	3
β-strand	55-56	2	6
β-strand	62-70	9	6
β-strand	78-83	6	7
β-strand	91-94	4	7

Chain C: 0 helices, 1 β-strand

Element	Residues	Length	Sheet
β-strand	5	1	8

Chain E: 10 helices, 36 β-strands

Element	Residues	Length	Sheet
β-strand	4-5	2	9
β-strand	11-14	4	10
β-strand	19-25	7	9
β-strand	32-38	7	10
β-strand	45-50	6	10
β-strand	54-58	5	9
β-strand	61-66	6	9
β-strand	71-76	6	9
α-helix	81-83	3
β-strand	85-92	8	10
β-strand	95	1	8
α-helix	100-101	2
β-strand	102-103	2	10
β-strand	107-112	6	10
β-strand	144-146	3	11
β-strand	149-153	5	12
β-strand	158-163	6	11
α-helix	164-165	2
β-strand	170-176	7	12
β-strand	183-189	7	12
β-strand	192-195	4	12
β-strand	204-207	4	11
β-strand	214-218	5	11
α-helix	223-225	3
β-strand	227-234	8	12
β-strand	241-242	2	12
β-strand	246-251	6	12
α-helix	254-256	3
β-strand	258	1	13
α-helix	259-260	2
β-strand	261-265	5	14
α-helix	266-268	3
α-helix	269-273	5
β-strand	277-287	11	14
β-strand	288	1	13
β-strand	292-298	7	15
β-strand	301-302	2	15
β-strand	307-309	3	14
β-strand	314-315	2	14
β-strand	325-334	10	14
α-helix	335-339	5
β-strand	345-351	7	15
β-strand	354	1	16
α-helix	365-366	2
β-strand	368	1	16
β-strand	370-376	7	15

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
MHC class I antigen	A	protein	276	Homo sapiens	A0A5B8RNS7 (AlphaFold model)
Beta-2-microglobulin	B	protein	100	Homo sapiens	P61769 (AlphaFold model)
Piwi-like protein 1	C	protein	9	Homo sapiens	Q96J94 (AlphaFold model)
TCR (3-domain single chain)	E	protein	382	Homo sapiens

Sequence of entity 1 (A), FASTA

>9SOK_1 MHC class I antigen (chains A)
GSHSMRYFFTSVSRPGRGEPRFIAVGYVDDTQFVRFDSDAASQRMEPRAPWIEQEGPEYW
DGETRKVKAHSQTHRVDLGTLRGYYNQSEAGSHTVQRMYGCDVGSDWRFLRGYHQYAYDG
KDYIALKEDLRSWTAADMAAQTTKHKWEAAHVAEQLRAYLEGTCVEWLRRYLENGKETLQ
RTDAPKTHMTHHAVSDHEATLRCWALSFYPAEITLTWQRDGEDQTQDTELVETRPAGDGT
FQKWAAVVVPSGQEQRYTCHVQHEGLPKPLTLRWEP

Sequence of entity 2 (B), FASTA

>9SOK_2 Beta-2-microglobulin (chains B)
MIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKD
WSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

Sequence of entity 3 (C), FASTA

>9SOK_3 Piwi-like protein 1 (chains C)
SLSNRLYYL

Sequence of entity 4 (E), FASTA

>9SOK_4 TCR (3-domain single chain) (chains E)
MAKEVEQNSGPLSVPEGAIASLNCTYSDRGSQSFFWYRQYSGKSPELIMSIYSNGDKEDG
RFTAQLNKASQYVSLLIRDSQPSDSATYLCAVNDSNFGNEKLTFGTGTRLTIIPNIQNPD
PGSSGGGGSGGGGSGGGGSTNAGVMQNPRHLVRRRGQEARLRCSPMKGHSHVYWYRQLPE
EGLKFMVYLQKENIIDESGMPKERFSAEFPKEGPSILRIQQVVRGDSAAYFCASSAGTTE
QYFGPGTRLTVTEDLNKVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVN
GKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQDPRNHFRCQVQFYGLSENDE
WTQDRAKPVTQIVSAEAWGRAD

Primary citation

Isolation of Human TCRs specific to any peptide-HLA complex. Karuppiah, V. Nat Commun (2026).

Other PDB entries of the same protein (UniProt A0A5B8RNS7 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9GV7 1.86 Å, Structure of reverse docking TCR in complex with peptide-HLA
6TMO 2.1 Å, Structure determination of an enhanced affinity TCR, a24b17, in complex with HLA-A*02:01…
9DL1 2.3 Å, Crystal Structure of HLA-A*02:01/NY-ESO-1 (SLLMWITQV) and a target specific TRACeR-I
9GV6 2.77 Å, Structure of TCR in complex with peptide-HLA
9SOL 2.93 Å, Structure of TCR-581 in complex with Peptide-HLA

Browse structure collections

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